It is an object of the present invention to provide coding techniques which allow for higher efficiency and easier synchronization with coded data. In order to attain the object, a coding device according to the present invention converts 2-bit informational data into 4-bit coded data according to a predetermined coding rule. According to the coding rule employed in the coding device, one of four possible kinds of bit strings of informational data is converted into alternately a bit string of four bits in which each of values of two successive bits is “1” and a bit string of four bits in which each of values of all bits is “0”. Then, the other kinds of bit strings are converted into bit strings of four bits which differ from one another, in each of which a value of only one bit is “1”.
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1. A coding device comprising
a first and a second converters for converting informational data of n (N≧2) bits into coded data of m (M≧2n−1) bits according to a predetermined coding rule, wherein
said first converter converts one kind of 2n possible kinds of bit strings of said informational data into alternately a bit string of m bits in which each of respective values of L (2≦L≦M) bits in successive bit positions is one of “0” and “1” and a bit string of m bits in which each of respective values of all bits is the other of “0” and “1”; and
said second converter converts each of the other kinds of said 2n possible kinds of bit strings of said informational data into bit strings of m bits which differ from one another, in each of which a value of only one bit or each of respective values of K (2≦K<L) in successive bit positions is said one of “0” and “1”.
2. The coding device according to
a relationship of M≧2n is established, and
said first and said second converters encode said informational data such that a value of a predetermined bit in said coded data is always said other of “0” and “1”.
3. The coding device according to
a third converter for converting said informational data into a bit string of m bits in violation of said predetermined coding rule.
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This application claims the benefit under 35 U.S.C. Section 371, of PCT International Application Number PCT/JP2007/068663, filed Sep. 26, 2007 and Japanese Application Nos. 2006-283755 filed Oct. 18, 2006 and 2006-335998 filed Dec. 13, 2006 in Japan, the contents of which are incorporated herein by reference.
The present invention relates to techniques for coding informational data of plural bits according to a predetermined coding rule, and to techniques for regenerating a pulse signal generated at a transmitting end, at a receiving end.
Conventionally, various techniques regarding a method of coding data which is to be transmitted through a communication channel have been suggested. For example, Patent documents 1 and 2 disclose a coding method which is called a pulse position modulation (PPM) method. According to a PPM method, respective pieces of 2-bit data representing “00”, “01”, “10”, and “11” are converted into respective pieces of 4-bit data representing “1000”, “0100”, “0010”, and “0001”, for example.
On the other hand, Patent documents 3 and 4 disclose a coding method which is called a coded mark inversion (CMI) method. According to a CMI method, 1-bit data representing “1” is converted into alternately 2-bit data representing “11” and 2-bit data representing “00”, and 1-bit data representing “0” is converted into 2-bit data representing “01”.
Patent document 3 also discloses a technique for transmitting a frame sync signal by utilizing coding rule violation (CRV).
In the meantime, in a communications system, there is a need for a technique for regenerating a pulse signal which has been generated at a transmitting end, at a receiving end, in some cases. In an infrared communications system as described in Patent document 2, for example, binary data is transmitted from a transmitting end by causing infrared light to flash, and then, at a receiving end, the infrared light transmitted from the transmitting end is received and binary data is generated from a signal of the received infrared light. Since binary data can be regarded as a pulse signal, it is possible to obtain binary data transmitted from the transmitting end by regenerating the pulse signal which has been generated at the transmitting end, based on the signal of the received light at the receiving end.
Patent Document 1: Japanese Patent Application Laid-Open No. 2000-134186
Patent Document 2: Japanese Patent Application Laid-Open No. 2000-267771
Patent Document 3: Japanese Patent Application Laid-Open No. 8-18611
Patent Document 4: Japanese Patent Application Laid-Open No. 2002-94488
In a case where a PPM method as described above is employed, efficiency in coding is high because data of plural bits is coded at a time. However, four kinds of bit strings represented by coded data have the same number of bits representing “1” and the same number of bits representing “0”. As such, it is impossible to detect a reference phase which is required for synchronization with the coded data, from those four kinds of bit strings, to present a problem of a difficulty in achieving synchronization with the coded data.
On the other hand, in a case where a CMI method is employed, bit strings represented by coded data include bit strings “11” and “00” each of which is different in the number of bits representing “1” or “0” from a bit string “01”. Accordingly, it is possible to detect a reference phase by utilizing those bit strings. Thus, a CMI method has an advantage that synchronization with the coded data can be easily achieved in decoding the coded data. Nonetheless, there is a problem of low efficiency in coding because 1-bit data is coded.
Also, in a communications system, it is required that regeneration of a pulse signal which has been generated at a transmitting end, at a receiving end, be timed as regularly as possible, in some cases. For example, in a case where binary data is obtained by regenerating a pulse signal as described above, if regeneration of the pulse signal is mistimed, omission, double reading, or the like of received data is likely to occur, so that received data may be incorrectly recognized.
The present invention has been made in view of the foregoing problems, and has a first object of providing coding techniques which allow for high efficiency in coding and easier synchronization with coded data. Further, it is a second object of the present invention to provide techniques which allow for reduction in errors in timing for regeneration of a pulse signal which has been generated at a transmitting end, at a receiving end.
In order to solve the above-described problems, a first example of a coding device according to the present invention includes a part for converting informational data of N (N≧2) bits into coded data of M (M≧2N1) bits according to a predetermined coding rule, wherein according to the predetermined coding rule, one of 2N possible kinds of bit strings of the informational data is converted into alternately a bit string of M bits in which each of respective values of L (2≦L≦M) bits in successive bit positions is one of “0” and “1” and a bit string of M bits in which each of respective values of all bits is the other of “0” and “1”; and the other kinds of the 2N possible kinds of bit strings of the informational data are converted into bit strings of M bits which differ from one another, in each of which a value of only one bit or each of respective values of K (2≦K<L) in successive bit positions is the one of “0” and “1”.
A second example of the coding device according to the present invention is the first example wherein a relationship of M≧2N is established in the predetermined coding rule, and the informational data is coded such that a value of a predetermined bit in the coded data is always the other of “0” and “1”.
A third example of the coding device according to the present invention is the first or second example which further includes a part for converting the informational data into a bit string of M bits in violation of the predetermined coding rule.
A first example of a pulse regenerating device according to the present invention is intended to regenerate a first pulse signal which is generated at a transmitting end of a communications system, the pulse regenerating device being provided at a receiving end of the communications system, wherein the first pulse signal is converted into a plurality of second pulse signals having a predetermined period at the transmitting end and the second pulse signals are input to the pulse regenerating device through a transmission line, and the pulse regenerating device includes: a serial-parallel converter which detects input of a given second pulse signal, and outputs in parallel the second pulse signals including the given second pulse signal which are serially input for a predetermined time period from the time of detecting input of the given second pulse signal; a regeneration determiner for determining whether or not the first pulse signal is regenerated based on the number of the second pulse signals which are output in parallel from the serial-parallel converter; and a regenerated pulse supplier for generating a third pulse signal as a regenerated signal of the first pulse signal when the regeneration determiner determines that the first pulse signal is regenerated.
A second example of the pulse regenerating device according to the present invention is the first example wherein the serial-parallel converter outputs in parallel the second pulse signals after shaping the second pulse signals.
In the first or second example of the pulse regenerating device according to the present invention, it is preferable that each of the second pulse signals is an optical signal, the pulse regenerating device further comprises a photoelectrical converter for converting the second pulse signals into electrical signals, and the electrical signals into which the second pulse signals are converted are input to the serial-parallel converter.
A communications system according to the present invention includes: a transmitting device for generating a first pulse signal, converting the first pulse signal into a plurality of second pulse signals having a predetermined period, and outputting the second pulse signals; and a receiving device for regenerating the first pulse signal from the second pulse signals which are input from the transmitting device through a transmission line, wherein the receiving device includes: a serial-parallel converter which detects input of a given second pulse signal and outputs in parallel the second pulse signals including the given second pulse signal which are serially input for a predetermined time period from the time of detecting input of the given second pulse signal; a regeneration determiner for determining whether or not the first pulse signal is regenerated based on the number of the second pulse signals which are output in parallel from the serial-parallel converter; and a regenerated pulse supplier for generating a third pulse signal as a regenerated signal of the first pulse signal when the regeneration determiner determines that the first pulse signal is regenerated.
According to the first example of the coding device of the present invention, informational data of plural bits is coded at a time, which allows for higher efficiency in coding.
Further, when a certain kind of bit string of the informational data is coded, a bit string in which more bits successively represent the same value than bit strings obtained by coding the other kinds of bit strings of the informational data, can be obtained. Thus, with the use of the certain kind of bit string of the informational data, it is possible to detect a reference phase required for synchronization with coded data. Therefore, synchronization with the coded data can be easily achieved in decoding the coded data.
Further, even if informational data of N bits is successively coded, a value of a binary code in the resultant coded data varies without fail. Thus, errors in data in decoding the coded data can be reduced.
Further, with respect to the coded data, possible patterns of bit strings of M bits include a pattern which can not be generated according to the coding rule of the present invention. Thus, with the use of the pattern which can not be generated, it is possible to make error correction in decoding the coded data.
According to the second example of the coding device of the present invention, the value of the predetermined bit in the coded data does not vary. Thus, with the use of the predetermined bit, it is possible to detect a reference phase required for synchronization with the coded data in decoding the coded data. Therefore, synchronization with the coded data can be more easily achieved.
Further, a relationship of M≧2N is established, the number of patterns which can not be generated according to the coding rule of the present invention, out of possible patterns of bit strings of M bits, is increased. Thus, it is possible to make sufficient error correction in decoding the coded data.
According to the third example of the coding device of the present invention, possible patterns of bit strings of M bits of the coded data include many patterns which can not be generated according to the coding rule of the present invention. Thus, it is possible to generate data in violation of coding rule by various methods.
According to the first example of the pulse regenerating device and the communications system of the present invention, it is determined whether or not the first pulse signal should be regenerated based on the number of the second pulse signals which are output in parallel from the serial-parallel converter. Accordingly, a determination as to regeneration of the first pulse signal can be made at a point in time when the second pulse signals which are serially input to the serial-parallel converter are output in parallel from the serial-parallel converter. Therefore, it is possible to reduce errors in timing for regeneration of the first pulse signal.
Further, since it is determined whether or not the first pulse signal should be regenerated based on the number of the second pulse signals, erroneous regeneration of the first pulse signal can be prevented even if an unnecessary pulse signal is caused on the transmission line. Also, even if the second pulse signal having a different pulse width is input, the first pulse signal can be regenerated. Further, even if some of the second pulse signals which are generated at the transmitting end vanish on the transmission line, the first pulse signal can be surely regenerated.
According to the second example of the pulse regenerating device of the present invention, the second pulse signal is output from the serial-parallel converter after being shaped. Thus, even if the pulse width of the second pulse signal varies on the transmission line, the regeneration determiner can exactly determine the number of the second pulse signals. Therefore, erroneous regeneration of the first pulse signal can be prevented.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
With respect to coded data CDD which is coded according to the foregoing rule, it is possible to obtain the informational data IFD by decoding the coded data CDD according to a rule reverse to the foregoing rule.
<Generalization of Coding Rule>
Next, the coding rule according to the present invention which is used for coding the informational data IFD of N (N≧2) bits in the coding device 350 will be described in a more generalized way. According to the present coding rule, the N-bit informational data IFD is converted into the coded data CDD of M (M≧2N−1) bits. In the above preferred embodiment, the coding rule in a case where N=2 and M=4 has been described.
According to the present coding rule, any one kind out of 2N possible kinds of bit strings of the N-bit informational data IFD is converted into alternately a bit string of M bits in which each of respective values of L (2≦L≦M) bits in successive bit positions is one of “0” and “1” and a bit string of M bits in which each of respective values of all bits is the other of “0” and “1”. In the above-described preferred embodiment, out of four (=22) possible kinds of bit strings of the 2-bit informational data IFD, a bit string “11” is converted into alternately a bit string “1100” of four bits (M=4) in which each of respective values of successive two bits (L=2) in the highest bit position and the second highest bit position is “1” and a bit string “0000” of four bits in which each of respective values of all bits is “0”.
Out of 2N possible kinds of bit strings of the informational data IFD, the other kinds of bit strings than that cited above are converted into bit strings of M bits which differ from one another, in each of which a value of only one bit or each of respective values of K (2≦K<L) bits in successive bit positions is the one of “0” and “1” (out of “0” and “1”, the same value of each of respective values of L bits in successive bit positions as described above). In the above-described preferred embodiment, out of four possible kinds of bit strings of the 2-bit informational data IFD, the other bit strings than the bit string “11”, that is, the bit strings “00”, “01”, and “10” are respectively converted into different bit strings each of four bits, “1000”, “0100”, and “0010” in each of which a value of only one bit is “1”. It is noted that N, M, and L are integers satisfying the above-described requirements.
<Effects of the Present Coding Rule>
As is made clear from the above description, the coding rule according to the present invention, in which the informational data IFD of N (N≧2) bits, in other words, plural bits, is coded at a time, provides for higher efficiency in coding than that in a CMI method in which 1-bit data is coded.
Further, according to the present coding rule, any one of 2N possible kinds of bit strings of the N-bit informational data IFD is converted into a bit string of M bits in which each of respective values of L bits in successive bit positions is one of “0” and “1”. As such, as a result of coding the one kind of bit string, a bit string including more bits which successively represent “1” can be obtained, as compared to a case in which the other kinds of bits strings are coded. For example, in the example shown in
As described above, according to the present coding rule, as a result of coding a certain kind of bit string of the informational data IFD, a bit string which has a larger number of bits successively representing the same value than that obtained by coding any other kinds of bit strings. Therefore, it is possible to detect a reference phase which is required for synchronization with the coded data CDD by utilizing the certain kind of bit string. Detailed description in this respect will be made as below.
Now, consider a case where a coding rule according to which the informational data IFD of “11” is always converted into “0001” is employed in the example shown in
In decoding a bit string shown in
According to the present coding rule shown in
Additionally, according to the coding rule shown in
Further, according to the present coding rule, even in a case where the informational data IFD of N bits is successively coded, a value of a binary code changes in the resultant coded data CDD without fail, so that errors in data when decoding the coded CDD data can be reduced.
For example, assuming that the informational data IFD of “11” is always converted into “0000” according to the coding rule shown in
In contrast, according to the coding rule shown in
Further, possible patterns of bit strings of M bits of the coded data CDD include a pattern which can not be generated according to the present coding rule. As such, in decoding the coded data CDD, error correction can be made by using the pattern which cannot be generated according to the present coding rule. For example, with respect to the 4-bit coded data CDD, only five patterns of bit strings “1000”, “0100”, “0010”, “1100”, and “0000” are used in the coding rule shown in
As shown in
Additionally, it is preferable to code the informational data IFD such that a value of a predetermined bit in the coded data CDD always represents the other of “0” and “1” (i.e., out of “0” and “1”, the value which is different from the value of each of the above-described L bits in successive bit positions), as in the examples shown in
Further, in a case where the informational data IFD is coded such that the value of a predetermined bit in the coded data CDD is always the other of “0” and “1”, a relationship of “M≧2N” is established, which results in an increase in the number of possible patterns of bit strings of M bits which can not be generated according to the present coding rule. For example, in the coding rules shown in
Coding Rule Violation (CRV)>
In an optical transmission device described in the above-cited Patent document 3, a CMI method is employed as a method of coding informational data. In a CMI method, informational data of “1” is converted into alternately “11” and “00”, and informational data of “0” is converted into “01”. Such methods of generating data in violation of the foregoing coding rule include a method called “CRV0” and a method called “CRV1”. In CRV0, data in violation of coding rule is generated by converting informational data of “0” into “10”, not “01”. On the other hand, in CRV1, data in violation of coding rule is generated by successively converting information data of “1” into either “11” or “00”, instead of converting information data of “1” into alternately “11” and “00”.
As is described above, informational data is converted into 2-bit coded data according to the coding rule in a CMI method. Thus, there is some limit to the number of employable methods of generating data in violation of coding rule to some degree.
According to the coding rule according to the present invention, the informational data IFD is converted into the coded data CDD of M bits and relationships of “M≧2N−1” and “N≧2” are established, so that the informational data IFD is converted into the coded data of three or more bits. Also, with respect to the coded data CDD, there are many possible patterns of bit strings which can not be generated according to the present coding rule. Therefore, generation of data in violation of coding rule can be achieved by more various methods as compared to a case in which data in violation of coding rule in a CMI method is generated. Below, a method of generating data in violation of coding rule will be specifically described by taking the coding rule shown in
In the above-described coding device 350, for example, data in violation of coding rule can be generated by converting the informational data IFD of “00” which is supposed to be converted into “1000” under normal conditions, into “1001”, for example. In the decoding device 351, not only the coded data CDD of “1000”, but also the coded data CDD of “1001”, is converted into the informational data IFD of “00”. As a result, the informational data IFD of “00” which has a given special significance, such as a frame sync signal, can be input to the decoding device 351, distinctly from the other pieces of informational data IFD of “00”.
In an alternative example, data in violation of coding rule can be generated by converting the informational data IFD of “01” which is supposed to be converted into “0100” under normal conditions, into “0101”, for example.
In another alternative example, data in violation of coding rule can be generated by converting the informational data IFD of “10” which is supposed to be converted into “0010” under normal conditions, into “0011”, for example.
In another alternative example, data in violation of coding rule can be generated by converting the informational data IFD of “11” which is supposed to be converted into “1100” under normal conditions, into “1101”, for example.
In another alternative example, data in violation of coding rule can be generated by converting the informational data IFD of “11” which is supposed to be converted into “0000” under normal conditions, into “0001”, for example.
In another alternative example, data in violation of coding rule can be generated by converting the informational data IFD of “11” which is supposed to be converted into alternately “1100” and “0000” under normal conditions, successively into either “1100” or “0000”, for example.
<Application of Present Invention>
Next, an example of a system which employs the coding device 350 and the decoding device 351 according to the present invention will be described. The following description will deal with a case where the coding device 350 and the decoding device 351 according to the present invention are used in an electronic shelf label (ESL) system which is introduced into supermarkets, convenience stores, and the like.
As shown in
Each of the electronic shelf labels 5 is a portable device, and can be detached from the frame 62 to be relocated in a different position, to keep up with a location change of the product 6. According to the first preferred embodiment, a plurality of shelves configured like the shelf 60 as shown in
The store controller 2 is formed of a typical computer, and functions as a device which totally controls the store information system 100. Also, the store controller 2 is connected to an external network such as Internet, and is allowed to communicate with computers such as servers, which are installed in a head office that manages a store, via an external network.
The POS system 3 is a system which collects and analyzes information regarding sale of products at the time of selling the products. The POS system 3 includes a plurality of cash registers 32 for performing checkout procedures of products, in addition to the POS server 31 which totally controls the POS system 3. The POS server 31 and the cash registers 32 are connected with each other via a dedicated communications cable.
The POS server 31 is formed of a typical computer, and contains a hard disk in which a product master 301 indicating a variety of information regarding products such as selling prices is stored. In each of the plurality of cash registers 32, checkout procedures of products are performed based on selling prices listed in the product master 301.
Information regarding all products in a store are under centralized control with the use of the product master 301. Information listed in the product master 301 includes “product codes” which are identification information of products, “product names” which are names of products, “regular prices” which are selling prices in normal times, “bargain prices” which are selling prices provided at the time of bargain sale, a “bargain period” which is a period for bargain sale, and the like.
The electronic shelf label system 1 is roughly divided into the plurality of electronic shelf labels 5 which have been described above and a distribution device 40 for distributing “selling prices” of products which should be displayed on the electronic shelf labels 5.
The distribution device 40 includes the ESL server 10 which is a server for totally controlling the ESL system 1 and a plurality of communications devices 4. The ESL server 10 and the communications devices 4 are connected with each other via a dedicated communications cable 22, so that data can be communicated between the ESL server 10 and the communications devices 4. Each of the communications devices 4 performs infrared communication with the electronic shelf labels 5. The communications devices 4 are placed on a ceiling of a selling floor or the like at substantially regular intervals so that the communications devices 4 can communicate with all the electronic shelf labels 5 located in the selling floor.
A structure of the ESL server 10 as a hardware is similar to that of a typical computer.
A dedicated program is previously stored in the hard disk 14 of the ESL server 10, and the CPU 11 performs computations in accordance with the dedicated program, so that various functions of the ESL server 10 are implemented. Also, the hard disk 14 of the ESL server 10 stores a product file 101 which is a data file indicating a variety of information regarding products (product data).
Each record 102 of the product file 101 further stores a “device code” which is a hardware ID unique to each of the electronic shelf labels 5 included in the electronic shelf label system 1. As a result, products and the electronic shelf labels 5 are in one-to-one correspondences (are linked with each other) in the form of data. With the use of the “device code”, a “selling price” of a given product is transmitted to one of the electronic shelf labels 5 which corresponds to the given product.
Next, the communications devices 4 will be described in detail.
The coding device 350 codes data indicating a “selling price” which is provided from the ESL server 10 according to the above-described coding rule, and outputs the coded data to the driving part 41. The driving part 41 drives the infrared light emitting element 42 based on the coded data as input. As a result, the infrared light emitting element 42 outputs an infrared signal IR1 which is modulated by the coded data provided from the coding device 350.
The infrared light receiving element 43 receives an infrared signal IR2 which is output from the electronic shelf label 5, and converts the received infrared signal IR2 into an electrical signal ES, which is then output to the data regenerating part 44. The data regenerating part 44 amplifies the received electrical signal ES, regenerates the coded data which is generated in the electronic shelf label 5 based on the amplified electrical signal ES, and outputs the regenerated coded data to the decoding device 351. The decoding device 351 decodes the coded data as input and outputs the decoded data to the ESL server 10. It is noted that, the coding rule according to the present invention is used for generation of the coded data also in the electronic shelf label 5, which will also be described later.
Next, the electronic shelf label 5 will be described.
The communications device 54 includes an infrared light emitting element 52 for transmitting the infrared signal IR2 and an infrared light receiving element 53 for receiving the infrared signal IR1 from the communications device 4. The infrared light emitting element 52 is formed of an LED, for example. The infrared light receiving element 53 is formed of a photodiode, for example, and converts the infrared signal IR1 into an electrical signal.
Onto a lower portion of the display part 51, an overlay label 55 on which a “product name” and a bar code indicating a “product code” of a product corresponding to the electronic shelf label 5 is printed is put. If a label or the like is not put on the electronic shelf label 5, it is difficult to see which of products corresponds to the electronic shelf label 5. However, as a result of provision of the overlay label 55, the electronic shelf label 5 and a product visually correspond to each other.
Also, the electronic shelf label 5 includes a compact battery 56 for supplying driving power and a control part 57 formed of an integrated circuit for controlling operations of a device inside the electronic shelf label 5. The control part 57 includes the above-described coding device 350 and the above-described decoding device 351, and further includes a driving part and a data regenerating part which operate in the same manner as the communications device 4, though those cited components are not shown. The control part 57 amplifies an electrical signal output from the infrared light receiving element 53 in the data regenerating part, regenerates the coded data which is generated in the communications device 4 based on the amplified electrical signal, and decodes the regenerated coded data in the decoding device 351, to thereby acquire data indicating a “selling price”. Further, the control part 57, upon receipt of the data indicating a “selling price”, generates data indicating the receipt, and codes the generated data in the coding device 350. Then, the control part 57 drives the infrared light emitting element 52 based on the code data generated in the coding device 350 with the use of the driving part, and outputs the infrared signal IR2 from the infrared light emitting element 52. Moreover, the control part 57 includes a memory 58 for storing a variety of information. The memory 58 stores data indicating a “selling price” which is obtained based on the infrared signal IR1, data indicating a device code of its own device, and the like. The control part 57 reads out the data indicating a “selling price” from the memory 58, and controls the display part 51 based on the read data. As a result, a “selling price” is displayed on the display part 51.
Next, a series of operations of the electronic shelf label system 1 for achieving display of a selling price on the electronic shelf label 5 will be described. In the electronic shelf label system 1 according to the first preferred embodiment, a “selling price” is distributed from the distribution device 40 to each of the electronic shelf labels 5 at the time of start-up of the system, at the time of updating a “selling price” which is to be displayed on the electronic shelf label 5, and at the other like times. It is noted that updating of a “selling price” is needed when a regular price listed in the product master 301 is changed or when a selling price is changed from a regular price to a bargain price for bargain sale. At the time of start-up of the system, “selling prices” of all products in a store are distributed. On the other hand, at the time of updating a “selling price”, only “selling prices” of products, which should be updated, are distributed. As a result, “selling prices” displayed on the electronic shelf labels 5 always match “selling prices” which are supposed to be provided at the time of checkout in the cash registers 32. The following description will deal with operations for distributing a “selling price” of one given product. In the following description, a product, of which selling price should be distributed, will be referred to as a “target product”.
First, the record 102 regarding the target product in the product file 101 is referred to, and a “selling price” which is either a “regular price” or a “bargain price” that should be distributed, and a “device code” are acquired, in the ESL server 10 of the distribution device 40. The thus acquired “device code” is a “device code” of one of the electronic shelf labels 5 which corresponds to the target product, and the acquired “selling price” is a “selling price” which should be displayed on the one electronic shelf label 5. The acquired “selling price” and “device code” are transmitted as electrical signals to the communications device 4 via the communications cable 22.
The signals indicating the “selling price” and the “device code” are coded in the communications device 4. The communications device 4 controls the infrared light emitting element 52 based on resultant coded data. As a result, the communications device 4 outputs the infrared signal IR1 including information about the “selling price” and the “device code”.
The infrared signal IR1 output from the communications device 4 is received by the communications part 54 of the electronic shelf label 5 and converted into an electrical signal. The control part 57 regenerates the coded data which is generated in the communications device 4, based on the electrical signal obtained in the communications part 54, and decodes the coded data, to thereby acquire data indicating the “selling price” and the “device code”.
Subsequently, the control part 57 determines whether or not the acquired “device code” matches a device code of its own device which has been previously stored in the memory 58. If the acquired “device code” does not match the device code of its own device, the received infrared signal IR1 is determined to be a signal for the other electronic shelf label 5, to terminate a process.
On the other hand, if the acquired “device code” matches the device code of its own device, the received infrared signal IR1 is determined to be a signal for its own device, and display of the display part 51 is updated by the control part 57 based on the acquired “selling price”.
By the above-described operations, distribution of a “selling price” from the distribution device 40 to the electronic shelf label 5 is achieved.
After display of the display part 51 is updated, the infrared signal IR2 including information indicating successful receipt of the data indicating the “selling price” is output from the infrared light emitting element 52 of the electronic shelf label 5. The infrared signal IR2 is received by the communications device 4, and the information included in the infrared signal IR2 is transmitted to the ESL server 10. As a result, the ESL server 10 of the distribution device 40 can confirm whether or not the data indicating the “selling price” is successfully received by the electronic shelf label 5. Thus, when the infrared signal IR2 is not output from the electronic shelf label 5, for example, the ESL server 10 determines that the data indicating the “selling price” is not successfully received by the electronic shelf label 5, and is allowed to perform a process of repeatedly outputting the data indicating the “selling price” or the other like processes until the infrared signal IR2 is received. In this manner, display on the electronic shelf label 5 can be surely updated, resulting in considerable improvement in reliability of the system.
As described above, as a result of use of the coding method according to the present invention in communication of information between the distribution device 40 and the electronic shelf label 5, a rate of data transmission between the distribution device 40 and the electronic shelf label 5 can be considerably improved. In particular, in a case where a display of a dot matrix type is employed as the display part 51 of the electronic shelf label 5, an amount of displayed data is significantly increased as compared to a case where a segment display is employed. As such, to employ the coding method according to the present invention in communication of information between the distribution device 40 and the electronic shelf label 5 would bring about remarkable effects.
It is additionally noted that though the above description has dealt with a case where the coding method according to the present invention is applied to an electronic shelf label system as an example, the coding method according to the present invention is applicable to the other systems, of course.
The transmitting device 150 includes a data generating part 151 for generating data which is to be transmitted to the receiving device 160, a data coding part 152 for coding data generated in the data generating part 151 according to a predetermined coding rule, a light emitting part 153 for outputting light, and a light-emission control part 154 for controlling the light emitting part 153 based on data which is coded in the data coding part 152.
The data generating part 151 generates binary data and outputs the generated binary data to the data coding part 152, as the informational data IFD. The data coding part 152 generates the coded data CDD by coding the informational data IFD according to the same coding rule that is employed in the coding device 350 according to the first preferred embodiment, and outputs the coded data CDD. The data coding part 152 employs the coding rule shown in
With respect to the coded data CDD which is obtained by coding according to the coding rule shown in
The light emitting part 153 is formed of an LED, for example, and outputs a pulse signal LP composed of infrared light under the control of the light-emission control part 154 based on the coded data CDD. Additionally, the other kinds of pulse signals such as a pulse signal composed of visible light or a pulse signal composed of ultraviolet light may alternatively be output from the light emitting part 153.
In the second preferred embodiment, while the short pulse signal EPS is input to the light-emission control part 154, a plurality of pulse signals LP each having a period T are output from the light emitting part 153 under the control of the light-emission control part 154 over the light emitting part 153. Likewise, while the long pulse signal EPL is input to the light-emission control part 154, a plurality of pulse signals LP each having a period T are output from the light emitting part 153 under the control of the light-emission control part 154 over the light emitting part 153.
Now, assume that the pulse width EPWS of the short pulse signal EPS is set to (NS×T) and the pulse width EPWL of the long pulse signal EPL is set to (NL×T). Each of “NS” and “NL” is an integer equal to or larger than three, and a relationship of “NS<NL” is established. The light emitting part 153 lights up the number of times smaller than NS with the period T while the short pulse signal EPS is input to the light-emission control part 154. As a result, a pulse number PNS which is the number of the pulse signals LP output from the light emitting part 153 while the short pulse signal EPS is input to the light-emission control part 154 is smaller than NS. Likewise, the light emitting part 153 lights up the number of times smaller than NL with the period T while the long pulse signal EPL is input to the light-emission control part 154. As a result, a pulse number PNL which is the number of the pulse signals LP output from the light emitting part 153 while the long pulse signal EPL is input to the light-emission control part 154 is smaller than NL.
As described above, as a result of control of the light-emission control part 154 over the light emitting part 153 based on the coded data CDD, the short pulse signal EPS is converted into the pulse signals LP, the number of which is smaller than NS, and the long pulse signal EPL is converted into the pulse signals LP, the number of which is smaller than NL. Then, the plurality of pulse signals LP are serially output to a transmission line TL provided between the transmitting device 150 and the receiving device 160. According to the second preferred embodiment, NS is equal to four, so that the short pulse signal EPS is converted into (NS−1) pulse signals LP, that is, three pulse signals LP, as shown in
As is made clear from the foregoing description, as a result of conversion of the short pulse signal EPS having a pulse width of (NS×T) into the pulse signals LP, the number of which is smaller than NS, the pulse number PNS regarding the pulse signals LP at that time is relatively small. Likewise, as a result of conversion of the long pulse signal EPL having a pulse width (NL×T) into the pulse signals LP, the number of which is smaller than NL, the pulse number PNL regarding the pulse signals LP at that time is relatively small. Therefore, a time period of light emission in the light emitting part 153 is shortened, to thereby reduce power consumption of the transmitting device 150.
Next, the receiving device 160 will be described in detail. As shown in
The light receiving part 161 receives the pulse signals LP fed from the transmitting device 150 via the transmission line TL. The light receiving part 161 is formed of a photodiode and an amplifier, for example, and converts the received pulse signals LP into electrical signals to output them serially, as pulse signals REP, to the pulse regenerating part 162. Thus, the light receiving part 161 functions as a photoelectrical converter which converts the pulse signals LP which are optical pulse signals, into electrical signals.
The pulse regenerating part 162 regenerates the short pulse signal EPS and the long pulse signal EPL based on the input pulse signals REP, and outputs the short pulse signal EPS and the long pulse signal EPL to the data decoding part 163. Since regeneration of the short pulse signal EPS and the long pulse signal EPL would result in regeneration of the coded data CDD which is generated in the transmitting device 150, the coded data CDD is regenerated in the pulse regenerating part 162. Then, the regenerated data is input as a regenerated coded data RCDD to the data decoding part 163.
The data decoding part 163 has the same functions as the above-described decoding device 351, and thus, decodes the regenerated coded data RCDD according to the coding rule described above with reference to
The pulse regenerating part 162 will be described in detail.
Each of the delay circuits 170i through 170o outputs an input signal which is delayed by a predetermined time period. In the second preferred embodiment, each of the delay circuits 170i through 170o outputs an input signal which is delayed by (2×Pw).
The pulse signals REP are serially input to each of the pulse shaping circuit 170a and the delay circuit 170i. Respective outputs of the delay circuits 170i through 170n are provided to the delay circuits 170j through 170o, respectively. Then, respective outputs of the delay circuits 170j through 170o are provided to the pulse shaping circuits 170b through 170h, respectively. In the serial-parallel converter 170, the pulse shaping circuit 170a is the first member that receives the pulse signals REP, and thus, input of the pulse signals REP to the serial-parallel converter 170 can be detected in the pulse shaping circuit 170a.
Now, remember that the pulse width of the pulse signal LP which is generated in the light emitting part 153 of the transmitting device 150 is set to Pw, and also, the period T of the pulse signal LP is set to (2×Pw), in the second preferred embodiment. Accordingly, without any change in the pulse width while the pulse signal LP is passing through the transmission line TL, the pulse signal REP obtained by converting the pulse signal LP into an electrical signal should have the pulse width Pw and the period of (2×Pw). However, actually, the pulse signal LP is likely to be subjected to some change while it is passing through the transmission line TL, and the pulse width thereof is likely to be decreased. Therefore, the pulse width of the pulse signal REP becomes smaller than Pw in some cases.
According to the second preferred embodiment, since the pulse signal REP can be shaped by the pulse shaping circuits 170a through 170h, the pulse signal REP having the pulse width Pw that the pulse signal REP should have can be obtained even if the pulse width of the pulse signal LP changes while the pulse signal LP is passing through the transmission line TL.
The pulse signal REP output from the light receiving part 161 is input to the pulse shaping circuit 170a as it is, and also is delayed by (2×Pw) in the delay circuit 170i, to be input to the pulse shaping circuit 170b. Then, after the delayed pulse signal REP is input to the pulse shaping circuit 170b, the delayed pulse signal REP is further delayed by (2×Pw) in the delay circuit 170j, to be input to the pulse shaping circuit 170c.
As described above, the period of the pulse signal REP is (2×Pw), which is equal to a delay time given in each of the delay circuits 170i through 170o. Accordingly, in a case where each of all the plurality of pulse signals LP which are generated in the transmitting device 150 with a period of (2×Pw) is input to the receiving device 160 without vanishing on the transmission line TL, at the same time when one of the pulse signals REP which is firstly input to the serial-parallel converter 170 is output from the pulse shaping circuit 170b, another of the pulse signals REP which is secondly input to the serial-parallel converter 170 is output from the pulse shaping circuit 170a. Then, at the same time when the first pulse signal REP is output from the pulse shaping circuit 170c after passing through the delay circuit 170j, the second pulse signal REP is output from the pulse shaping circuit 170b and further, the third pulse signal REP is output from the pulse shaping circuit 170a. Thereafter, in the same manner as described above, when the first pulse signal REP is output from the pulse shaping circuit 170h, the pulse signals REP which are input to the serial-parallel converter 170 from the time of input of the first pulse signal REP to the pulse shaping circuit 170a to the time of input of the first pulse signal REP to the pulse shaping circuit 170h are simultaneously output from the pulse shaping circuits 170a through 170g, respectively. Respective output signals of the pulse shaping circuits 170a through 170h are input as signals SA through SH to the regeneration determiner 171, respectively.
The serial-parallel converter 170 according to the second preferred embodiment operates such that, when input of a certain pulse signal REP is detected in the pulse shaping circuit 170a, the pulse signals REP (including the certain pulse signal REP) which are serially input in a predetermined time period from the time of the detection of the certain pulse signal REP are output in parallel. Since the seven delay circuits 170i through 170o are provided and a delay time given in each of the delay circuits is set to (2×Pw) in the second preferred embodiment, the serial-parallel converter 170 outputs in parallel the pulse signals REP (including the certain pulse signal REP) which are serially input in a time period of (7×2×Pw) from the time of detection of input of the certain pulse signal REP.
In the transmitting device 150, the short pulse signal EPS is converted into three pulse signals LP each having a period of (2×Pw) as described above. Accordingly, in a case where the three pulse signals LP are serially input to the receiving device 160, at the same time when the pulse signal REP which is related to the leading one out of the three pulse signals LP is output from the pulse shaping circuit 170h of the serial-parallel converter 170, the other two pulse signals REP are output from the pulse shaping circuits 170f and 170g, respectively.
On the other hand, in the transmitting device 150, the long pulse signal EPL is converted into seven pulse signals LP each having a period of (2×Pw). Accordingly, in a case where the seven pulse signals are serially input to the receiving device 160, at the same time when the pulse signal REP which is related to the leading one out of the seven pulse signals LP is output from the pulse shaping circuit 170h, the other six pulse signals REP are output from the pulse shaping circuits 170b through 170g, respectively.
Next, the regeneration determiner 171 will be described in detail.
The AND circuit 171g calculates and outputs AND of the signals SE and SF, the AND circuit 171h calculates and outputs AND of the signals SE and SG, and the AND circuit 171i calculates and outputs AND of the signals SF and SG. The AND circuit 171j calculates and outputs AND of the signals SE and SH, the AND circuit 171k calculates and outputs AND of the signals SF and SH, and the AND circuit 171l calculates and outputs AND of the signals SG and SH.
The OR circuit 171n calculates and outputs OR of output signals of the AND circuits 171b and 171c, and the OR circuit 1710 calculates and outputs OR of output signals of the AND circuits 171d, 171e, and 171f. The OR circuit 171p calculates and outputs OR of output signals of the AND circuits 171h and 171i, and the OR circuit 171q calculates and outputs OR of output signals of the AND circuits 171j, 171k, and 171l.
The delay circuit 171t outputs an output signal of the AND circuit 171a which is delayed by (4×Pw), and the delay circuit 171u outputs an output signal of the OR circuit 171n which is delayed by (2×Pw). The delay circuit 171v outputs an output signal of the AND circuit 171g which is delayed by (4×Pw), ant the delay circuit 171w outputs an output signal of the OR circuit 171p which is delayed by (2×Pw).
The OR circuit 171r calculates and outputs OR of an output signal ST of the delay circuit 171t, an output signal SU of the delay circuit 171u, and an output signal SO of the OR circuit 171o, and the OR circuit 171s calculates and outputs OR of an output signal SV of the delay circuit 171v, an output signal SW of the delay circuit 171w, and an output signal SQ of the OR circuit 171q. Then, the AND circuit 171m calculates and outputs AND of an output signal SR of the OR circuit 171r and an output signal JS1 of the OR circuit 171s. An output signal JS0 of the AND circuit 171m and the output signal JS1 of the OR circuit 171s are input to the regenerated pulse supplier 172.
In the regeneration determiner 171 configured as described above, when the pulse signals REP are simultaneously output from at least two of the pulse shaping circuits 170a through 170d, in other words, when at least two of the signals SA through SD simultaneously enter to “High” level, an output of the OR circuit 171r enters to “High” level. Also, when the pulse signals REP are simultaneously output from at least two of the pulse shaping circuits 170e through 170h, in other words, when at least two of the signals SE through SH simultaneously enter to “High” level, an output of the OR circuit 171s enters to “High” level. Then, as the respective outputs of the OR circuits 171r and 171s simultaneously enter to “High” level, an output of the AND circuit 171m enters to “High” level.
According to the second preferred embodiment, each of the output signal JS0 of the AND circuit 171m and the output signal JS1 of the OR circuit 171s functions as a signal which indicates whether or not the long pulse signal EPL and the short pulse signal EPS should be regenerated. Specifically, when the regeneration determiner 171 determines that the long pulse signal EPL should be regenerated, both the output signals JS0 and JS1 are set at “High” level. On the other hand, when the regeneration determiner 171 determines that the short pulse signal EPS should be regenerated, the output signal JS0 is set at “Low” level and the output signal JS1 is set at “High” level. As such, in the regenerated pulse supplier 172, when both the output signals JS0 and JS1 enter to “High” level, the long pulse signal EPL is regenerated, and when only the output signal JS1 enters to “High” level, the short pulse signal EPS is regenerated.
In the regenerated pulse supplier 172 configured as described above, when the output signals JS0 and JS1 simultaneously enter to “High” level, the pulse signal REPL having a large pulse width is output as a regenerated signal of the long pulse signal EPL from the OR circuit 172c. On the other hand, when only the output signal JS1 enters to “High” level, the pulse signal REPS having a small pulse width is output as a regenerated signal of the short pulse signal EPS from the OR circuit 172c. The pulse signal REPL and the pulse signal REPS will be hereinafter referred to as a “regenerated long pulse signal REPL” and a “regenerated short pulse signal REPS”.
The short pulse signal EPS is converted into three pulse signals LP in the transmitting device 150 as described above. After at least two of the three pulse signals LP are serially input to the receiving device 160 and the pulse signal REP which is related to the leading pulse signal LP of the at least two is output from the pulse shaping circuit 170h, the output signal JS0 enters to “Low” level and the output signal JS1 enters to “High” level in the regeneration determiner 171. In other words, the regeneration determiner 171 determines that the short pulse signal EPS should be regenerated when the number of the pulse signals REP arising from the short pulse signal EPS, which are output in parallel from the serial-parallel converter 170, is equal to or larger than two.
In examples shown in
On the other hand, in the case where the leading pulse signal LP vanishes as shown in
The long pulse signal EPL is regenerated on different conditions from those for the short pulse signal EPS. Specifically, when at least two out of the first four pulse signals LP in the seven pulse signals LP into which the long pulse signal EPL is converted are input to the receiving device 160 and at least two out of the remaining three pulse signals LP are input to the receiving device 160, the long pulse signal EPL is regenerated basically. However, even under the foregoing conditions, unless the output signals of the OR circuits 171r and 171s of the regeneration determiner 171 simultaneously enter to “High” level, the long pulse signal EPL is not regenerated.
For example, in a case where the second pulse signal LP and the fifth pulse signal LP out of the seven pulse signals LP arising from the long pulse signal EPL vanish, the output signals of the OR circuits 171r and 171s do not simultaneously enter to “High” level, so that the long pulse signal EPL is not regenerated. Also, in a case where the leading pulse signal LP and the seventh pulse signal LP out of the seven pulse signals LP vanish, the output signals of the OR circuits 171r and 171s do not simultaneously enter to “High” level, so that the long pulse signal EPL is not regenerated. Further, in a case where the leading and second pulse signals LP vanish, the output signals of the OR circuits 171r and 171s do not simultaneously enter to “High” level regardless of the presence or absence of the fifth, sixth, and seventh pulse signals LP, so that the long pulse signal EPL is not regenerated.
As described above, according to the second preferred embodiment, the long pulse signal EPL is regenerated on conditions which are greatly different from those under which the short pulse signal EPS is regenerated. This is because the same circuit that is required for regenerating the short pulse signal EPS is used for regenerating the long pulse signal EPL. As shown in
As described above, according to the second preferred embodiment, whether or not the short pulse signal EPS should be regenerated is determined based on the number of the pulse signals REP arising from the short pulse signal EPS, which are output in parallel from the serial-parallel converter 170. As such, it is possible to make a determination as to regeneration of the short pulse signal EPS at the point in time when the pulse signals REP arising from the short pulse signal EPS, which are serially input to the serial-parallel converter 170, are output in parallel from the serial-parallel converter 170 (i.e., a time t8 in the examples in
In the examples shown in
Further, according to the second preferred embodiment, whether or not the short pulse signal EPS should be regenerated is determined based on the number of the pulse signals REP. As such, even if an unnecessary pulse signal LP is caused on the transmission line TL, it is possible to prevent erroneous regeneration of the short pulse signal EPS. Also, even if the pulse signals LP having different pulse widths are input to the receiving device 160, the short pulse signal EPS can be regenerated. Moreover, even if some of the plurality of pulse signals LP which are generated on the side of the transmitting device 150 vanish on the transmission line TL, the short pulse signal EPS can be surely regenerated.
Furthermore, according to the second preferred embodiment, the pulse signals REP are output from the serial-parallel converter 170 after being shaped. As such, even if the pulse width of the pulse signal LP changes on the transmission line TL, the regeneration determiner 171 can exactly determine the number of the pulse signals REP. Thus, erroneous regeneration of the short pulse signal EPS can be suppressed.
Additionally, though each of the short pulse signal EPS and the long pulse signal EPL is converted into a plurality of optical pulse signals in the transmitting device 150 according to the second preferred embodiment, each of the pulse signals may alternatively be converted into a plurality of electrical pulse signals. In this alternative case, the light receiving part 161 for converting an optical signal into an electrical signal in the receiving device 160 is unnecessary.
Also, though two kinds of pulse signals of the short pulse signal EPS and the long pulse signal EPL are regenerated in the second preferred embodiment, if only one kind of pulse signal which is generated at a transmitting end is required to be regenerated at a receiving end, the structure of the pulse regenerating part 162 can be simplified. For example, if only the short pulse signal EPS is required to be regenerated, the pulse shaping circuits 170a through 170d and the delay circuits 170i through 170l in the serial-parallel converter 170, the AND circuits 171a through 171f and 171m, the OR circuits 171n, 171o, and 171r, and the delay circuits 171t and 171u in the regeneration determiner 171, and the one-shot pulse generating circuit 172a and the OR circuit 172c in the regenerated pulse supplier 172 are unnecessary.
<Modification of Pulse Regenerating Part>
Next, another example of a structure of the pulse regenerating part 162 will be described.
As shown in
Each of the flip-flop circuits 270a through 270j holds and outputs a signal input to a data input terminal D thereof at a rising edge of the clock signal CLK1. On the other hand, the flip-flop circuit 270k holds and outputs a signal input to a data input terminal D thereof at a falling edge of the clock signal CLK1. The pulse signal REP is input to the data input terminal D of each of the flip-flop circuits 270a and 270k. The OR circuit 270m calculates and outputs OR of output signals of the flip-flop circuits 270a and 270k, and an output signal of the OR circuit 270m is input to the data input terminal D of the flip-flop circuit 270b. The flip-flop circuits 270b through 270j are serially connected in the order noted, and each of the flip-flop circuits 270b through 270j holds and outputs an output signal fed from a preceding stage at a rising edge of the clock signal CLK1. The OR circuit 270l calculates and outputs OR of an output signal of the OR circuit 270m and an output signal of the flip-flop circuit 270b. The OR circuit 270n calculates and outputs OR of output signals of the flip-flop circuits 270e and 270f. The OR circuit 270o calculates and outputs OR of output signals of the flip-flop circuits 270i and 270j.
It is noted that the respective output signals of the flip-flop circuits 270a and 270k will be referred to as a “signal SSA” and a “signal SSB”, and the output signal of the OR circuit 270m will be referred to as a “signal SSC”. Also, the respective output signals of the flip-flop circuits 270b through 270j will be referred to as “signals SSD through SSL”, respectively. Further, the respective output signals of the OR circuits 270l, 270n, and 270o will be referred to as “signals SSM, SSN, and SSO”, respectively.
The regeneration determiner 271 includes AND circuits 271a and 271b and an OR circuit 271c as shown in
The regenerated pulse supplier 272 includes flip-flop circuits 272a through 272d, OR circuits 272e through 272f, and a clock generator 272i, as shown in
Each of the flip-flop circuits 272a, 272b, and 272c holds and outputs a signal input to a data input terminal D thereof at a rising edge of the clock signal CLK1. On the other hand, the flip-flop circuit 272d holds and outputs a signal input to a data input terminal D thereof at a rising edge of the clock signal CLK2. The signal SSR is input to the data input terminal D of the flip-flop circuit 272a. The flip-flop circuits 272a, 272b, and 272c are serially connected in the order noted, and each of the flip-flop circuits 272a, 272b, and 272c holds and outputs an output signal fed from a preceding stage at a rising edge of the clock signal CLK1.
The OR circuit 272e calculates and outputs OR of the signal SSR and a signal SSS which is the output signal of the flip-flop circuit 272a, and the OR circuit 272f calculates and outputs OR of a signal SST which is the output signal of the flip-flop circuit 272b and a signal SSU which is the output signal of the flip-flop circuit 272c. Then, the OR circuit 272g calculates OR of the respective output signals of the OR circuits 272e and 272f, and outputs the result as a signal SSV.
The signal SSV is input to a data input terminal D of the flip-flop circuit 272d. The OR circuit 272h calculates OR of the signal SSV and a signal SSW which is the output signal of the flip-flop circuit 272d, and outputs the result as a signal SSX.
Next, operations of the modification of the pulse regenerating part 162 which are shown in
The serial-parallel converting circuit 270 shown in
In the examples shown in
On the other hand, in the example shown in
In the serial-parallel converting circuit 270, following detection of input of a given pulse signal REP, the pulse signals REP (including the given pulse signal REP) which are serially input for a time period of (4×Pw) from the time of the detection are output in parallel from the OR circuits 270l, 270n, and 270o. At that time, the pulse signals REP are output after being shaped so as to have a predetermined pulse width. The serial-parallel converting circuit 270 outputs the pulse signals REP each having a pulse width of (7/4×Pw) as shown at the signals SSM, SSN, and SSO in
In the examples shown in
On the other hand, in the example shown in
In the regeneration determiner 271, when two or more pulse signals REP are output in parallel from the serial-parallel converting circuit 270, that is, when at least two of the signals SSM, SSN, and SSO simultaneously enter to “High” level, it is determined that the short pulse signal EPS should be regenerated and the signal SSR is raised to “High” level. Then, after the signal SSR enters to “High” level, the regenerated pulse supplier 272 generates a pulse signal having a short pulse width, and outputs the generated pulse signal as a regenerated signal of the short pulse signal EPS from the AND circuit 272h (refer to the signal SSX).
As a regenerated signal of the short pulse signal EPS, a pulse signal having a pulse width which is 29/4 times as long as Pw is generated in the example shown in
In the modification of the pulse regenerating part 162 shown in
Additionally, though the serial-parallel converting circuit 270 shown in
Also, the serial-parallel converting circuit 270 may alternatively be formed of circuitry shown in
The pulse signal REP is input to a data input terminal D of each of flip-flop circuits 270a1, 270a2, 270k1, and 270k2. The flip-flop circuit 270a1 holds and outputs a signal input to the data input terminal D thereof at a rising edge of an output signal of the flip-flop circuit 270r. The flip-flop circuit 270a2 holds and outputs a signal input to the data input terminal D thereof at a rising edge of an output signal of the flip-flop circuit 270s. The flip-flop circuit 270k1 holds and outputs a signal input to the data input terminal D thereof at a rising edge of an output signal of the flip-flop circuit 270t. The flip-flop circuit 270k2 holds ant outputs a signal input to the data input terminal D thereof at a rising edge of a non-inverted output signal of the flip-flop circuit 270u. Then, the OR circuit 270m calculates OR of the output signals of the flip-flop circuits 270a1, 270a2, 270k1, and 270k2, and outputs the result as the signal SSC. The other respects in structure are the same as shown in
As is described above, the serial-parallel converting circuit can be formed with the use of the clock signal CLK4 having a period which is one-eighth of Pw, in other words, the clock signal CLK4 at quadruple speed relative to the clock signal CLK1.
<Application of Present Invention>
Next, an example of a system in which the transmitting device 150 and the receiving device 160 according to the present invention are employed will be described. The following description will deal with a case where the transmitting device 150 and the receiving device 160 are employed in the electronic shelf label system 1 in the above-described store information system 100. The following description will deal with the electronic shelf label system 1 in which the transmitting device 150 and the receiving device 160 are employed according to the second preferred embodiment, while mainly focusing on differences from the electronic shelf label system 1 according to the first preferred embodiment described above.
The data coding part 441 codes data indicating a “selling price” which is provided from the ESL server 10 according to the coding rule shown in
The light receiving part 444 receives a pulse signal LP2 of infrared light which is output from the electronic shelf label 5. The pulse signal LP2 is generated in the same manner as the pulse signal LP1. The light receiving part 444 converts the pulse signal LP2 of infrared light into an electrical signal, and outputs the electrical signal as a pulse signal REP2 to the pulse regenerating part 445. The pulse regenerating part 445 regenerates the short pulse signal EPS and the long pulse signal EPL which are generated in the electronic shelf label 5 from the input pulse signal REP2, and outputs the regenerated signals to the data decoding part 446. As a result, the coded data generated in the electronic shelf label 5 is input to the data decoding part 446. The data decoding part 446 decodes the coded data as input according to the above-described coding rule shown in
Next, the electronic shelf label 5 according to the second preferred embodiment will be described.
The communications part 554 includes a light emitting part 552 for outputting the pulse signal LP2 of infrared light and a light receiving part 553 for receiving the pulse signal LP1 from the communications device 4, converting the pulse signal LP1 into an electrical signal, and outputting the electrical signal. The light emitting part 552 has the same functions as the light emitting part 443 of the communications device 4, and the light receiving part 553 has the same functions as the light receiving part 444 of the communications device 4.
Onto a lower portion of the display part 551, an overlay label 555 on which a bar code indicating a “product name” and a “product code” of a product corresponding to the electronic shelf label 5 are printed are put. If a label or the like is not put on the electronic shelf label 5, it is difficult to see which of products corresponds to the electronic shelf label 5. However, because of provision of the overlay label 555, the electronic shelf label 5 and a product visually correspond to each other.
Also, the electronic shelf label 5 includes a compact battery 556 for supplying driving power and a control part 557 formed of an integrated circuit for controlling operations of the electronic shelf label 5. The control part 557 has the same functions as the pulse regenerating part 445 and the data decoding part 446 of the communications device 4. The control part 557 regenerates the short pulse signal EPS and the long pulse signal EPL which are generated in the communications device 4 based on an electrical signal output from the light receiving part 553, to acquire coded data. Then, the control part 557 decodes the coded data according to the above-described coding rule shown in
Furthermore, the control part 557 includes a memory 558 for storing a variety of information. The memory 558 stores data indicating a “selling price” which is obtained from the pulse signals LP1, data indicating a counterpart code of its own device, and the like. The control part 557 reads out data indicating a “selling price” from the memory 558, and controls the display part 551 based on the read data. As a result, a “selling price” is displayed on the display part 551.
Next, a series of operations of the electronic shelf label system 1 according to the second preferred embodiment, which operations are performed in order to display a selling price on the electronic shelf label 5, will be described. In the electronic shelf label system 1 according to the second preferred embodiment, like the first second preferred embodiment, a “selling price” is distributed from the distribution device 49 to the electronic shelf label 5 at the time of start-up, at the time of updating a “selling price” which is to be displayed on the electronic shelf label 5, and at the other like times. It is noted that updating of a “selling price” is needed when a regular price listed in the product master 301 is changed or when a selling price is changed from a regular price to a bargain price for bargain sale. At the time of start-up of the system, “selling prices” of all products in a store are distributed. On the other hand, at the time of updating a “selling price”, only “selling prices” of products, which should be updated, are distributed. As a result, “selling prices” displayed on the electronic shelf labels 5 always match “selling prices” which are supposed to be provided at the time of checkout in the cash registers 32. The following description will deal with operations for distributing a “selling price” of one given product. In the following description, a product, of which selling price should be distributed, will be referred to as a “target product”, and the terms “device code” which is used in the above description will be replaced by terms “counterpart code”.
First, the record 102 regarding the target product in the product file 101 is referred to, and a “selling price” which is either a “regular price” or a “bargain price” that should be distributed, and a “counterpart code” are acquired, in the ESL server 10 of the distribution device 40. The thus acquired “counterpart code” is a “counterpart code” of one of the electronic shelf labels 5 which corresponds to the target product, and the acquired “selling price” is a “selling price” which should be displayed on the one electronic shelf label 5. The acquired “selling price” and “counterpart code” are transmitted as electrical signals to the communications device 4 via the communications cable 22.
The signals indicating the “selling price” and the “counterpart code” are coded in the communications device 4. The communications device 4 controls the light emitting part 443 based on coded data obtained by coding in the communications device 4. As a result, the communications device 4 outputs the pulse signal LP1 containing information about the “selling price” and the “counterpart code”.
The pulse signal LP1 output from the communications device 4 is received by the communications part 54 of the electronic shelf label 5 and converted into an electrical signal. The control part 557 acquires data indicating the “selling price” and the “counterpart code” from the electrical signal obtained in the communications part 554.
Subsequently, the control part 557 determines whether or not the acquired “counterpart code” matches a counterpart code of its own device which has been previously stored in the memory 558. If the acquired “counterpart code” does not match the counterpart code of its own device, the received pulse signal LP1 is determined to be a signal for the other electronic shelf label 5, to terminate a process.
On the other hand, if the acquired “counterpart code” matches the counterpart code of its own device, the received pulse signal LP1 is determined to be a signal for its own device, and display of the display part 551 is updated by the control part 557 based on the acquired “selling price”.
By the above-described operations, distribution of a “selling price” from the distribution device 40 to the electronic shelf label 5 is achieved.
After display of the display part 551 is updated, the pulse signal LP2 containing information indicating successful receipt of the data indicating the “selling price” is output from the light emitting part 552 of the electronic shelf label 5. The pulse signal LP2 is received by the communications device 4, and the information contained in the pulse signal LP2 is transmitted to the ESL server 10. As a result, the ESL server 10 of the distribution device 40 can confirm whether or not the data indicating the “selling price” is successfully received by the electronic shelf label 5. Thus, when the pulse signal LP2 is not output from the electronic shelf label 5, for example, the ESL server 10 determines that the data indicating the “selling price” is not successfully received by the electronic shelf label 5, and is allowed to perform a process of repeatedly outputting the data indicating the “selling price” or the other like processes until the pulse signal LP2 is received. In this manner, display on the electronic shelf label 5 can be surely updated, resulting in considerable improvement in reliability of the system.
It is additionally noted that though the above description in the second preferred embodiment has dealt with a case where the transmitting device 150 and the receiving device 160 according to the present invention are applied to an electronic shelf label system as an example, those devices are applicable to the other systems, of course.
While the invention has been shown and described in detail, the foregoing description is in all aspects illustrative and not restrictive. It is therefore understood that numerous modifications and variations can be devised without departing from the scope of the invention.
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| Aug 07 2008 | MIZUKAWA, SHIGEMITSU | ISHIDA CO , LTD | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 021539 | /0825 |
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